[Effects of injectable calcium blockers on cardiac function and relaxation in left ventricular hypertrophy].

Nineteen patients with left ventricular hypertrophy were given intravenous calcium antagonists: 9 patients received intravenous verapamil (VPM IV) and 10 patients diltiazem (DTZ) by intracoronary and then intravenous injection. Systemic and pulmonary resistances, cardiac output, left ventricular and aortic pressures, isometric contractility, isometric relaxation and left ventricular compliance were studied in sinus rhythm, during atrial and then ventricular pacing at 120/min and finally after tachycardia before and after administration of calcium antagonists. Left ventriculography in the 30 degrees RAO projection in sinus rhythm was performed before and after injection of the calcium antagonists to study the variations in the end diastolic volume, mass and mass-volume ratio. Finally, frame by frame numerisation of the ventriculographies during systole and diastole helped evaluate variations in amplitude, time and velocity of fibre shortening or lengthening. The administration of the calcium antagonists did not have any significant effect on heart rate (-2.8 +/- 10 p. 100, NS) or indices of isometric contractility (delta Vmax + 4 +/- 43 p. 100, NS). Significant falls in systemic and pulmonary resistances (-15 +/- 23 p. 100, p less than 0.05 and - 26 +/- 32 p. 100, p less than 0.05, respectively) and an increase in systolic index (+ 15.5 p. 100 +/- 12 p. 100, p less than 0.01) were observed. The improvement in left ventricular ejection was independent of the variation in resistances but was closely related to variations of parameters of relaxation. The effects on volumic compliance and filling velocities were also closely related to variations in relaxation (p less than 0.05 and p less than 0.01). Calcium antagonists protected left ventricular ejection during supraventricular tachycardia and prevented the changes in left ventricular relaxation observed during arrhythmias and after tachycardia.(ABSTRACT TRUNCATED AT 250 WORDS)